What is TCP 53 used for?

What is TCP 53 used for?

The DNS uses TCP Port 53 for zone transfers, for maintaining coherence between the DNS database and the server. The UDP protocol is used when a client sends a query to the DNS server.

Is 53 UDP or TCP?

The answer is DNS is mostly UDP Port 53, but as time progresses, DNS will rely on TCP Port 53 more heavily.

What is port 55 used for?

Side note: UDP port 55 uses the Datagram Protocol, a communications protocol for the Internet network layer, transport layer, and session layer. This protocol when used over PORT 55 makes possible the transmission of a datagram message from one computer to an application running in another computer.

What is TCP 81 used for?

Well-known ports

Port TCP Description
80 Yes Hypertext Transfer Protocol (HTTP) uses TCP in versions 1.x and 2. HTTP/3 uses QUIC, a transport protocol on top of UDP.
81 Unofficial TorPark onion routing
82 TorPark control
83 Yes MIT ML Device, networking file system

Why does port 53 need to be open?

Port 53 is open for DNS. Why would I need this? You need to have UDP 53 allowed for responses to DNS queries that your server sends, as UDP is a stateless protocol. Don’t block it if you want any kind of outbound connectivity, software updates, etc.

What service runs on port 55?


Port Transport Protocol
55 TCP, UDP ISI Graphics Language.
56 TCP, UDP XNS Authentication.
57 TCP MTP, Mail Transfer Protocol.
58 TCP, UDP XNS Mail.

Can I use port 81?

Secure Web connections, usually indicated by “https” in the Web address rather than simply “http” and by a lock icon in the browser, typically use port 443. Port 81 is on the list as unreserved, but in practice it’s often used by specialized Web servers that are avoiding the standard port 80 for some reason.

How do I open port 81?

Open firewall ports in Windows 10

  1. Navigate to Control Panel, System and Security and Windows Firewall.
  2. Select Advanced settings and highlight Inbound Rules in the left pane.
  3. Right click Inbound Rules and select New Rule.
  4. Add the port you need to open and click Next.

What do you need to know about TCP port 53?

TCP Port 53. If you have information on TCP port 53 that is not reflected on this page, simply leave a comment and we’ll update our information. Port 53 is used by the Domain Name System (DNS), a service that turns human readable names like into IP addresses that the computer understands.

When does DNS switch to TCP or UDP port 53?

DNS has always been designed to use both UDP and TCP port 53 from the start 1 , with UDP being the default, and fall back to using TCP when it is unable to communicate on UDP, typically when the packet size is too large to push through in a single UDP packet. When Does DNS Switch to TCP?

What is port 53 in Kerio Personal Firewall?

Kerio Personal Firewall (KPF) 2.1.4 has a default rule to accept incoming packets from DNS (UDP port 53), which allows remote attackers to bypass the firewall filters via packets with a source port of 53.